Index: busybox-1.27.2/modutils/modprobe.c
===================================================================
--- busybox-1.27.2/modutils/modprobe.c
+++ busybox-1.27.2/modutils/modprobe.c	2017-10-26 00:51:33.903124109 +0530
@@ -216,6 +216,18 @@
 {
 	struct module_entry *m;
 
+	 /*
+	 * get_or_add_modentry() strips path from name and works
+	 * on remaining basename.
+	 * This would make "rmmod dir/name" and "modprobe dir/name"
+	 * to work like "rmmod name" and "modprobe name",
+	 * which is wrong, and can be abused via implicit modprobing:
+	 * "ifconfig /usbserial up" tries to modprobe netdev-/usbserial.
+	 */
+	if (strchr(name, '/'))
+	       bb_error_msg_and_die("malformed module name '%s'", name);
+
+
 	m = get_or_add_modentry(name);
 	if (!(option_mask32 & (OPT_REMOVE | OPT_SHOW_DEPS))
 	 && (m->flags & (MODULE_FLAG_LOADED | MODULE_FLAG_BUILTIN))